isc-hmac-fixup(8) on macOS

The text f5ce01a7107d, as Mac OS X 10.7.4, Mac OS X 10.7.3, Mac OS X 10.7.2, Mac OS X 10.7.1, Mac OS X 10.7 shipped it.

fixes HMAC keys generated by older versions of BIND

isc-hmac-fixup(8) on macOS now